Camera Exposure Modes


How to use a camera: exposure modes made simple

Buying a good camera and staying on auto settings is like buying a Porsche for the school run. We show you how to use a camera in a more meaningful way that lets you take control of the picture-taking process.
In this series we’ll run through all of your camera’s exposure modes and explain when – and why – you should use them.


Your digital camera’s auto settings make it easier to just point and shoot, and often that’s enough to capture a moment in time. But what if your subject’s moving, if the light is constantly changing or you want to get creative with blur?
If you’ve started to feel as if you’re missing out on photo opportunities because you can’t work out how to take control, it’s time to master your camera’s creative shooting options.
Choosing and using the different exposure modes can transform the pictures you take, but venturing off fully automatic modes can be daunting, and even experienced photographers can find choosing the right settings tricky.
So here we’ve put together a guide to the four main exposure modes, covering everything from taking control in Program mode to mastering full manual operation. It will forever change the way you shoot!
Before we get started, in the infographic below we’ve highlighted the icons you’re likely to see on your digital camera’s top dial and what they mean (click image to view larger version).

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How to use Program mode

Program mode can easily be dismissed as just a point and shoot option, as, on the face of it, it doesn’t give you any instant control over shutter speed or aperture. However, it’s not that simple.
In Program mode the camera chooses both the shutter speed and aperture according to its computer program (hence the name), to decide on the correct exposure.
If you don’t want to think about these settings, Program mode is perfect, but it has actually got much more to offer than just full automation.
The first advantage of Program mode is that, unlike the Scene modes or fully automatic ‘green’ mode, it allows you to use Exposure Compensation.
This enables you to override the suggested exposure, which is particularly useful when shooting predominantly light or dark subjects that can fool the camera’s exposure meter.
Program mode also gives you control over several other key creative features, such as the flash and white balance modes, which aren’t available in many of your camera’s fully automatic modes.
What’s it good for?

  • Situations where you don’t have time to select the aperture or shutter speed.
  • Shooting in changing lighting when you don’t need a specific shutter speed or aperture for creative effects.
  • Learning the basic relationship between the aperture and shutter speed.
  • Street photography and candids.

What’s it bad  for?

  • When you need full control over the shutter speed or aperture.
  • Learning to control the precise effects of blur and depth of field.

Using Program Shift / Flexible Program
Your first step to controlling the shutter speed and aperture in Program mode is to use a feature called Program Shift.
This gives you some control over the combination of shutter speed and aperture that the camera will use, without having to switch to one of the other exposure modes.
To access this on most cameras you simply turn the main input dial to shift the combination of aperture and shutter speed that the camera will use.
The main disadvantage of using Program Shift compared to either Shutter- or Aperture Priority is that when the light changes or you alter the framing to include darker or lighter areas most cameras will change the shutter speed, aperture or both to alter the exposure.
This means it’s more difficult to use a specific aperture or shutter speed in this mode, but it’s a great way to expand the creativity of using Program mode.
Program Shift is also perfect for those new to changing shutter speeds and apertures, as under normal lighting conditions it won’t let you select a shutter speed or aperture that’s beyond the range available to give the correct exposure.
This safety net isn’t present in other modes, so they aren’t as beginner-friendly.
Why do different settings give the same exposure?
One of the most confusing aspects of choosing the settings for the correct exposure is that there isn’t just a single combination of shutter speed and aperture that will give you the correct exposure.
At one particular ISO, there are several combinations of shutter speed and aperture that will give you the correct exposure.
For example, if you have your camera set ISO200, 1/250 sec at f/5.6 will give exactly the same exposure as 1/15 sec at f/22.
But the effect of the different shutter speeds and apertures will alter the appearance of your images, and is the reason the different exposure modes exist, as they give you complete control over which combination you want to use for creative effect.


What is Aperture Priority mode?
 The next step towards full manual control of your camera is using Aperture Priority mode to take more control over the depth of field in your image.
Aperture Priority mode is the most useful and convenient mode for shooting many subjects and situations. Changing the aperture gives you control over the depth of field, but the camera will select the shutter speed automatically.
The main advantage of using Aperture Priority mode is that it gives you control over the depth of field in your image, but also with the convenience of not having to set the shutter speed yourself.
Even though in Aperture Priority mode your main concern is the aperture setting, this doesn’t mean you should completely ignore the shutter speed.
The main concern is the shutter speed falling below a speed that you can safely hold the camera steady to avoid camera shake.
In this situation you have a few options: you can either increase the ISO, which will allow you to use a faster shutter speed at the same aperture, or keep the settings the same and use a tripod to prevent camera shake.

Highs and lows of Aperture Priority mode
You need to keep a close eye on the shutter speed when you are shooting in very dark or bright conditions.
In very bright conditions you need to check that the shutter speed display is showing a speed rather than ‘Hi’, or flashing to indicate there isn’t a shutter speed fast enough to give the correct exposure.
In this case, you’ll have to use a lower ISO, a smaller aperture or reduce the amount of light reaching the sensor by using a Neutral Density filter.
Similarly, in dark conditions the shutter speed display may flash or say ‘Lo’, indicating that there isn’t a shutter speed long enough to avoid under-exposure. In this situation you need to use a wider aperture or increase the ISO until a useable shutter speed is shown on the display.

How to control depth of field in Aperture Priority mode
1 Select the aperture
Set A or Av on the exposure mode dial and use the main input dial to select the aperture. This value will remain even if the camera can’t select a suitable shutter speed, so half-press the shutter to check that a shutter speed is also shown.
2 Apply Exposure Compensation
The metering will automatically adjust the shutter speed, but Exposure Compensation may be needed to increase or decrease the exposure. This will only affect the shutter speed, not the aperture.


 What is Shutter Priority mode?

Shutter Priority mode is simply the opposite of Aperture Priority mode, so instead of choosing the aperture you have control over the shutter speed.
This mode is most useful when you are shooting moving subjects, especially when you don’t have time to set the aperture manually – when shooting sports, wildlife or action, for example.
To freeze fast-moving subjects like birds in flight or motor racing you’ll need a fast shutter speed of 1/1000 sec or faster.
Remember that you may need to increase the ISO to allow you to use these fast shutter speeds, especially in low light.
You can also combine a slower shutter speed with a panning technique – where you follow the movement with your camera to blur the background while keeping the main subject sharp.
Try using a shutter speed of around 1/125 sec when panning with fast-moving subjects like motorbikes or cars, while you can try a slower speed such as 1/30 sec for slower moving subjects.
You can use Shutter Priority for long shutter speed effects such as blurring moving water, people or traffic.
You’ll need a shutter speed of 1/4 sec, or slower to blur many of these subjects, so you’ll have to mount the camera on a tripod, and ideally use a remote shutter release to ensure the static areas are pin sharp.

2 Using slow shutter speeds Check for a high exposure warning. If so, set a lower ISO if one is available or use a faster shutter speed, otherwise use a Neutral Density or polarising filter.

Pros and Cons of Shutter Priority mode

What’s it good for?

  • 
Shooting sports and action where you need control over the shutter speed

What’s it bad for?

  • 
Most landscape photography
  • Any subject where you need precise control over the depth of field

Extracted from “Digital Camera World” website for information purposes for members of Conwy Camera Club